as for physics - we don't have even standard unifying theory that would work in all situations, so there is some room to grow our knowledge. we observe a lot of powerful and strange stuff happening in cosmos, but these are natural things - matter seems to be doing couple of variations of same cycle - group by gravity till planet/star is born, exist for some time, explode/die slowly/collapse/go exotic. who can say what will happen when we literally take matter, energy and spacetime into our hands?
But before we will reach these situations, our society will change completely, probably many times. implants, prolonging life endlessly, going completely into digital existence and who knows what. why would inter-galaxy travel matter if we would exist in endless sea of some data banks?
Diversity in every way possible is in our Genes. Even within our own cultures, if it's possible for people to live a certain way you're highly likely to find at least some people living that way. Some of these ways of living seem pathalogical. Travelling people, isolationist survivalists, even homeless people but if civilization were to collapse, as it has many times in many places in the past, some of these people would be superbly adapted to survive it or even thrive.
For any given place, eventually catastrophe is almost inevitable. We are all the descendants of people who survived some catastrophe or other by moving out before it struck. All of us. In fact that's true of every surviving species on Earth. It's a strategy that works. Let's keep doing it.
If our understanding of fundamental physics is correct, there will never be an interstellar civilization of the sort that sci fi depicts. Only balkanized civilizations separated by many decades of travel. Within a solar system, no doubt interplanetary colonies will happen, but the conditions for life on other planets within our solar system are overwhelmingly harsh, difficult, and expensive.
Most of the work that needs to go into making either of those things happen will occur here on Earth. Although a Mars colony could help, if there was some economic imperative which could sustain and drive it.